Mast Syndrome, also known as spg21, is related to spastic paraplegia 34, x-linked and spastic paraplegia 14, autosomal recessive, and has symptoms including abnormal pyramidal signs An important gene associated with Mast Syndrome is SPG21 (SPG21 Abhydrolase Domain Containing, Maspardin). Affiliated tissues include brain and cerebellum, and related phenotypes are abnormal pyramidal sign and difficulty walking